Piranha 25K Ball Bearing Motor

[Racin67Chevy]

Thanks for the detailed review!

[Brumos RSR]

[Dogsbody]

[HomeRacingWorld]

We tested a bunch a few years back, not any significant differences, at least not enough to claim one side is really an advantage. Although again, when we are trying to race with magnets...anything goes. Magnet strength varies almost as much as the RPM variances in these motors. More advantage was seen in mounting the motor properly and reducing the distance between the motor and the rails.

In the case of this motor though...it is even more irrelevant. (if thats possible). Which way would you mount a standard can FC130 motor? Is there a plastic chassis where you would mount the top of the endbell upside down? Not to mention it has holes on each side of the can.

[RichD]

Since my club mostly runs on wood tracks with copper tape or tinned copper braid magnetic downforce from a motor would not be a factor. We have one wood track with Magnabraid and one Carrera track however, so any downforce due to a motor would be a concern on those. In most cases we use spec motors and that would tend to level the playing field. Any motor with a closed can is unlikely to have significant downforce. The 21.5K and 25K Piranha motors both have cases with holes on the top and bottom, but the 21.5K motor has negligible downforce while the 25K motor has significant downforce. A steel plate covering the holes would greatly attenuate the magnetic field and I am aware of a few clubs that are racing without magnets who would require using that with open can motors.

[Brumos RSR]

[HomeRacingWorld]

I don't have access to a meter anymore, but just going on "feel" I set a standard 21 and the new 25BB on a steel plate.
I can feel a slight difference in magnetic downforce. I can't prove it by the numbers, but I am pretty sure it is stronger.

I then took them apart and found the difference



On the left is the original 21 K and on the right, the new 25KBB. It appears the new one is using neodymium style and the original ferrite/ceramic.

Or that is what I am seeing. In any case, the 25KBB does have more downforce. With that armature removed from the can, it still has some (although reduced) downforce when just the can is laid on a metal plate. With the original, there is literally zero downforce until of course you install the armature back in.

[Perrotoro]

Thanks for endview pics

[Aloha]

Harry
Did you happen to change the armatures to see how they spec out? Curious to see what the 21.3 arm runs in the 25k can?
Thank you
Aloha
Dale

[Audi1]

I tested 3 of the new 25k Piranha motors a couple of weeks ago.

First I broke them in; light lube on both ends of the armature, 3.0V - 30 min, 4.5V - 30 min, 6.0V - 30 min, 7.5V - 15 min, 9.0V - 15 min and 12V - 15 min, then I used a digital tach to measure the rpm while the motors were still warm. At the end of that break-in period, the rpms on the 3 motors were:

1. 28.2k
2. 27.2k
3. 28.3k

So, these Piranha motors are running a lot, from an rpm spec parameter, like the 21.5k units; about 10% above manufacturer's spec. No complaints from me on that point.

I have yet to run one in a car, but if the ball bearing motor gives you anywhere near the quick spool-up that we used to enjoy with the Scaleauto blue S-can ball bearing motor, and if the powerband is as smooth and predictable as the 21.5k unit, then this will be a very nice motor for a lot of higher power applications.

Another thing that I like about this motor is that it runs cool for a high rpm motor. After the above break-in scheme, the 30k rpm Scaleauto S-can motor (I think it's the 0010B) runs very hot, but this one is just barely warm to the touch. No complaints on that point either....

Allan